Missing data commonly occurs in medical device trials, despite carefully designed and executed investigational plans. Missing data may relate to the performance of the device itself, or to clinical endpoints and/or diagnostic data collected from patients in the trial. Missing data is a potential source of bias, and must be considered in the evaluation of study results. Various approaches have been successfully applied to systematically evaluate the impact of missing data in studies supporting the clearance or approval of medical devices. The approach selected depends on the trial design, the reason(s) for missing data, and the nature of the data itself.